<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        body {
            margin: 0;
            height: 2000px;
        }
        
        .box {
            height: 50vh;
            width: 50vw;
            background-color: rgb(133, 44, 44);
        }
        
        .big {
            width: 600px;
            height: 400px;
            background-color: rgb(207, 181, 181);
        }
        
        .small {
            width: 50vw;
            height: 40%;
            background-color: rgb(35, 182, 101);
        }
        
        input[type=checkbox] {
            vertical-align: -2px;
        }
        
        .ib {
            border: 1px solid red;
            width: 100px;
            height: 100px;
            display: inline-block;
            vertical-align: bottom;
        }
    </style>
</head>

<body>
    <div class="box"></div>
    <div class="big">
        <div class="small"></div>
    </div>
    <form action="">

        <label for="username">用户名：</label><input type="text" id="username" name="username"><br>
        <label for="nan">男</label><input type="radio" id="nan" name="gender"><br>
        <label for="nv">女<input type="radio" id="nv" name="gender"></label><br>
        <input type="checkbox"> <span>同意以上协议可以注册</span>

        <div class="ib">一个文字</div>
        <div class="ib"></div>

    </form>
</body>

</html>